How to Switch back from Firefox driver to WebDriver(Appium Driver) Instance on AVD?

Hi All,
I am trying to switch back from Browser window to AVD (Running Application) but as if I send a mail from Mobile Application After Email Verification
on web browser to enter text fetched from Firefox browser when I return to AVD I am noticing Appium Server Shut-Down(Home Button Being Pressed as there is no command meanwhile).

So is it possible to make server session alive till the end of test execution and/or switch back controls on running Application on AVD.

Please Help.